Sheet separation method and sheet separation mechanism for automatic document feeder (adf)

ABSTRACT

A sheet separation method for an automatic document feeder (ADF) is provided. The ADF includes a sheet tray for supporting sheets, and a sheet separation surface for separating the sheets. A sheet separation angle is formed between the sheet separation surface and a placement surface of the sheet tray, and the sheet separation method comprises the steps of: (a) determining the characteristics of the sheets; and (b) adjusting the angle according to the characteristics of the sheets.

This application claims the benefit of People's Republic of China priority Ser. No. 200910152198.4, filed on Jul. 17, 2009, the subject matter of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates in general to a technology for guiding the separation of sheet, and more particularly to a sheet separation method for ADF and a sheet separation mechanism using the sheet separation method.

2. Description of the Related Art

Office machines such as copiers, fax machines, and scanners are normally equipped with an automatic document feeder (ADF) and a sheet separation mechanism for implementing the automatic feeding function of loading multiple sheets at one time but feeding only one sheet at a time. On the part of the sheet separation mechanism, a fixed sheet separation dam is disposed on one end of the sheet tray in the sheet feeding direction, and there is a contained angle between the sheet separation dam and the sheet tray. The contained angle between the sheet separation dam and the sheet horizontal direction is fixed, and during the separation process, the sheet retrieving roller retrieves the sheet from the sheet tray through the bevel of the separation dam and then separates the sheet by way of buckling. For example, when the contained angle between the sheet separation dam and the sheet tray is 110°, the 70 gsm A4 size sheet is smoothly separated.

The sheet with different thicknesses has different buckling strengths. While thin sheets are subjected to the problem that more than one sheet may be feeded at the same time, thick sheets are subjected to the gripping problem, and both problems would end up with interruption in printing. According to existing technologies, a separation plate with a number of resistive strips are obliquely disposed in the sheet feeding direction, wherein the friction coefficient of the separation plate is corrected by the resistive strips to satisfy thin sheets and thick sheets for separating each one of the sheets. However, in practical application, the contained angle between the separation dam and the sheet horizontal direction is fixed, and thin sheets and thick sheets still cannot be effectively separated by merely adjusting the friction coefficient of the separation plate.

SUMMARY OF THE INVENTION

The invention is directed to a sheet separation method for automatic document feeder (ADF) which adjusts the sheet separation angle according to the thickness of the sheet for smoothly separating the sheet with different thicknesses and effectively avoids the failure in the loading of one or more than one sheet.

The invention further provides a sheet separation mechanism for ADF. The sheet separation surface, being moveably and separately disposed with respect to the sheet tray, is adjustable so that the sheet separation mechanism can be adapted to the operation of separating the sheet with different thicknesses.

According to a first aspect of the present invention, a sheet separation method for ADF is provided. The ADF includes a sheet tray for supporting sheets, and a sheet separation surface for separating the sheets, a sheet separation angle is formed between the sheet separation surface and a placement surface of the sheet tray, and the sheet separation method includes the steps of: (a) determining the characteristics of the sheets; and (b) adjusting the angle according to the characteristics of the sheets.

According to a second aspect of the present invention, an ADF sheet separation mechanism for transporting sheets is provided. The sheet separation mechanism includes: a sheet tray and a sheet separation surface. The sheet tray has a placement surface for supporting the sheets. The sheet separation surface is moveably associated with the sheet tray, wherein a sheet separation angle is formed between the sheet separation surface and the placement surface according to the characteristics of the sheets.

According to a third aspect of the present invention, a sheet separation mechanism is provided. The sheet separation mechanism includes: a sheet tray, a sheet separation plate and a driving mechanism. The sheet tray has a placement surface for supporting sheets. The sheet separation plate has a separation surface for separating the sheets, wherein a sheet separation angle is formed between the separation surface and the placement surface. The driving mechanism coupled to one of the sheet tray and the sheet separation plate for changing the angle according to thicknesses of the sheets.

The ADF sheet separation method and the sheet separation mechanism of the invention have the following advantages: Through the sheet separation surface which is moveably and separatedly disposed with respect to the sheet tray, the sheet separation surface is adjustable and can be adapted to the operation of separating the sheets for different thicknesses smoothly, and effectively prevents the failure in loading one or more than one sheet.

The invention will become apparent from the following detailed description of the preferred but non-limiting embodiments. The following description is made with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a structural diagram of a sheet separation mechanism in one state according to an embodiment of the invention;

FIG. 2 shows a structural diagram of the sheet separation mechanism of FIG. 1 in another state;

FIG. 3 a structural diagram of a sheet separation mechanism in one state according to another embodiment of the invention;

FIG. 4 shows a 3D structural diagram of FIG. 3;

FIG. 5 shows a structural diagram of a sheet separation mechanism according to yet another embodiment of the invention; and

FIG. 6 shows a 3D structural diagram of FIG. 5.

DETAILED DESCRIPTION OF THE INVENTION

The sheet separation method for automatic document feeder (ADF) of the invention can be adopted the sheet separation mechanism to a fax machine, a scanner, a copier or a printer. The ADF, in present embodiment, includes a sheet tray and a sheet separation plate forming a sheet separation surface which forms an angle with respect to the sheet tray. The sheet separation plate and the sheet tray are rotatably connected such that the angle between the sheet separation surface and the sheet tray is adjustable. It should be appreciated that there are two embodiments to achieve aforementioned object. In one embodiment, the sheet tray is fixed and the sheet separation plate is movable. In the other embodiment, the sheet separation plate is fixed and the sheet tray is movable. In an embodiment, the sheet separation surface is formed on a sheet separation plate obliquely disposed on one end of the sheet tray in the sheet feeding direction. By rotating or moving the sheet separation plate, the contained angle between the sheet separation surface formed on the sheet separation plate and the sheet tray can be changed to separate each of the sheets for different thicknesses, based on the sheet buckling. Generally, the contained angle, between the sheet separation surface and the sheet tray, for thick sheet is larger than the contained angle for thin sheet. For example, 130° of the contained angle is used for thick sheet, and 110° of the contained angle is used for thin sheet. Using the method aforementioned, it will effectively prevent the circumstance that the sheets don't feed in device.

Referring to FIG. 1 and FIG. 2. In an embodiment, the sheet separation mechanism 100 of the ADF can be used in the sheet separation mechanism of a fax machine, a scanner, a copier or a printer for automatically feeding the sheets. The sheet separation mechanism 100 has a sheet tray 110, wherein the sheet tray 110 has a placement surface which is not movable, but not limited, and is used for supporting the sheets. A sheet feeding roller 130 disposed on the sheet tray 110. A sheet separation plate 120 is moveably disposed on one end of the sheet tray 110. The sheet separation plate 120, which is a movable mechanism, has a sheet separation surface. Thus, an adjustable sheet separation angle is formed between the sheet separation surface of the sheet separation plate 120 and the placement surface of the sheet tray. Alternatively, the sheet separation plate 120 is fixed and the placement surface of the sheet tray 110 can be adjustable, in which the angle contained between the sheet separation surface and the placement surface of the sheet tray can be adjustable. Also, the sheet separation plate 120 and the sheet tray 110 are movable for adjusting the angle. By adjusting the sheet separation angle, the sheets in different thicknesses can be precisely separated for feeding. The sheet separation mechanism 100 can be adapted in a fax machine, a scanner, a copier or a printer, and a sheet feeding roller can be disposed on the other end of the sheet separation surface for feeding the sheet. However, it should be appreciated that the sheet separation angle can be adjusted according to the characteristics of the sheet, such as material or stiffness.

Referring to FIG. 3 and FIG. 4. In another embodiment, the sheet separation mechanism 200 has a sheet tray 210 and a sheet separation plate 220. The top surface of the sheet tray 210 has a placement surface for supporting the sheet, and a sheet feeding roller 230 is disposed on the sheet tray. The sheet separation plate 220 is movably disposed on the sheet feeding end of the sheet tray, and has a sheet separation surface. Adjustable sheet separation angle is formed between the placement surface of the sheet tray and the sheet separation surface. By adjusting the sheet separation angle, the sheets in different thicknesses can be precisely separated for feeding. The sheet separation surface is located on a terminal surface of the sheet separation plate 220, and a driving mechanism 240 is disposed on one end of the sheet separation plate 220 for driving the sheet separation plate 220 to rotate around a connection axis, so that the angle between the sheet separation surface of the sheet separation plate 220 and the sheet tray 210 can be changed to separate each of the sheets for different thicknesses, based on the sheet buckling. In another embodiment, the driving mechanism 240 can also be disposed on the connection portion between the sheet tray 210 and the sheet separation plate 220 for changing the angle between the sheet separation surface of the sheet separation plate 220 and the sheet tray 210. One side of the driving mechanism is connected to a rotation grip 250 disposed on a side portion of the sheet tray 210. Rotating the rotation grip 250 drives the driving mechanism 240, which further drives the sheet separation plate 220 to rotate for changing the angle between the sheet separation surface and the placement surface.

Practically, an indication, corresponding to the thickness of the sheets, can be disposed on the one side of the rotation grip 250 or the sheet tray 210. Therefore, user can adjust the rotation grip 250 according to the indication of the thickness of the sheets loaded in the sheet tray so that the angle corresponding to the thickness of the sheets is reasonably and conveniently achieved.

Referring to FIG. 5 and FIG. 6. In another embodiment, the sheet separation mechanism 300 has a sheet tray 310 and a sheet separation plate 320. The top surface of the sheet tray 310 has a placement surface for supporting the sheet, and a sheet feeding roller 330 is disposed on the sheet tray. The sheet separation plate 320 is moveably disposed on the sheet feeding end of the sheet tray, and has a sheet separation surface. Adjustable sheet separation angle is formed between the placement surface of the sheet tray and the sheet separation surface. By adjusting the sheet separation angle, the sheets in different thicknesses can be precisely separated for feeding. The sheet separation surface is located on a terminal surface of the sheet separation plate 320, and a driving mechanism 340 is disposed on one end of the sheet separation plate 320 for driving the sheet separation plate to rotate around a connection axis, so that the angle between the sheet separation surface of the sheet separation plate 320 and the sheet tray 310 can be changed to separate each of the sheets for different thicknesses, based on the sheet buckling. The driving mechanism 340 is connected to a driving motor 350, and when the driving motor 350 is rotated, the driving mechanism 340 is driven to drive the sheet separation plate 320 for rotating the sheet separation surface around a connection axis. Furthermore, through an operation panel or an user interface software of the computer, the user can set the thickness of the sheets. After the setting is done, a signal is generated to inform the control unit of the scanner or the copier, and under the control of the control unit, the driving motor 350 forms an adjustable sheet separation angle between the sheet separation surface and the placement surface of the sheet tray. Sheet thickness detector 311, which can be realized by a refraction type or a projection type photo-electro detector, can be disposed on the sheet tray for automatically detecting the thickness of the sheet and then generating a signal to inform the control unit of the scanner or the copier. Under the control of the control unit, the driving motor 350 is driven for rotating the sheet separation plate 320 to predetermined degrees. In another embodiment, a sheet sensor can be further disposed on the terminal surface of the sheet separation plate 320 for determining whether the sheet passes through the sensor within a predetermined time. If not, this implies that the current thickness of sheet does not correspond to the current sheet separation angle, which results in sheet feeding fails, and then the control unit of the copier controls the driving motor 350 to adjust the sheet separation angle for feeding.

According to the ADF sheet separation method and the sheet separation mechanism thereof disclosed in the invention, the sheet separation surface is adjusted for separating the sheets in different thicknesses. Furthermore, the accuracy in sheet separation is increased, and the sheet is fed in one by one smoothly. However, a reasonable change in the angle between the sheet separation surface and the sheet tray can be implemented by another way in which the sheet separation surface is fixed and the sheet tray angle is movable for achieving the functions described as the foregoing mention.

While the invention has been described by way of example and in terms of a preferred embodiment, it is to be understood that the invention is not limited thereto. On the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures. 

1. A sheet separation method for an automatic document feeder (ADF), wherein the ADF comprises a sheet tray for supporting sheets and a sheet separation surface for separating the sheets, a sheet separation angle is formed between the sheet separation surface and a placement surface of the sheet tray, and the sheet separation method comprises the steps of: (a) determining the characteristics of the sheets; and (b) adjusting the angle according to the characteristics of the sheets.
 2. The sheet separation method according to claim 1, wherein the ADF further comprises a sheet separation plate obliquely disposed corresponding to the sheet tray for forming the sheet separation surface, and the sheet separation method in step(b) further comprises: driving the sheet separation plate for adjusting the angle.
 3. The sheet separation method according to claim 1, wherein the ADF further comprises a sheet separation plate obliquely disposed corresponding to the sheet tray for forming the sheet separation surface, and the sheet separation method in step(b) further comprises: manually driving the sheet separation plate for adjusting the angle.
 4. The sheet separation method according to claim 1, wherein the ADF is used in image processing device including a user interface, and the sheet separation method in step (a) further comprises: utiliting the user interface to set the characteristics of the sheets.
 5. The sheet separation method according to claim 4, wherein the ADF further comprises a sheet separation plate forming the sheet separation surface, and the sheet separation method in step (b) further comprises: driving the sheet separation plate or the sheet tray for adjusting the angle.
 6. A sheet separation mechanism for transporting sheets on an automatic document feeder (ADF), wherein the sheet separation mechanism comprises: a sheet tray having a placement surface for supporting the sheets; a sheet separation surface moveably associated with the sheet tray, wherein a sheet separation angle is formed between the sheet separation surface and the placement surface according to the characteristics of the sheets.
 7. The sheet separation mechanism according to claim 6, wherein the sheet separation mechanism further comprises a sheet separation plate forming the sheet separation surface and a driving mechanism coupled to the sheet separation plate for adjusting the angle.
 8. The sheet separation mechanism according to claim 7, wherein the driving mechanism is coupleded to a rotation grip, and the angle between the sheet separation surface and the placement surface is changed using the rotation grip.
 9. The sheet separation mechanism according to claim 7, wherein the ADF comprises a sheet thickness detector and a control unit which controls the driving mechanism to change the angle between the sheet separation surface and the placement surface according to detected thicknesses of the sheets by the detector.
 10. The sheet separation mechanism according to claim 6, wherein a sheet feeding roller is disposed on the sheet tray, and the sheet separation surface is disposed on a front end of the sheet tray in a sheet feeding direction.
 11. The sheet separation mechanism according to claim 6, wherein the sheet separation mechanism can be adapted to a fax machine, a scanner, a copier or a printer.
 12. The sheet separation mechanism according to claim 6, wherein the sheet tray is moveably disposed, and a driving mechanism is coupled to the sheet tray for adjusting the angle.
 13. The sheet separation mechanism according to claim 6, wherein the characteristics of the sheets includes thicknesses of the sheets.
 14. A sheet separation mechanism, comprising: a sheet tray having a placement surface for supporting sheets; a sheet separation plate having a separation surface for separating the sheets, wherein a sheet separation angle is formed between the separation surface and the placement surface; and a driving mechanism coupled to one of the sheet tray and the sheet separation plate for changing the angle according to thicknesses of the sheets.
 15. The sheet separation mechanism according to claim 14, wherein the sheet separation mechanism is used in image processing device including a user interface and a control unit, wherein the user interface is used for setting the thicknesses of the sheets, and the driving mechanism is driven by the control unit according to the thicknesses of the sheets in the user interface. 